C.P. Sentinel (Potential Control) Series

This series of rectifier stands as a “sentinel” to guard your assets from corrosion and ensure the operator selected output level is maintained. This rectifier series is widely customizable to meet a broad range of client requirements. For applications where precise and stable control of the “ON” or “IR-Drop Free” structure to reference electrode potential is required, the C.P. Sentinel series is the one for you.

The C.P. Sentinel (Potential) Series rectifiers are available with air-cooled or oil-cooled type construction.

C.P. Sentinel Air Series:

• The standard C.P. Sentinel Air Series enclosure is constructed from 12 gauge mill-galvanized steel with a white fusion bond polyester powder coating and conforms to a Type 3R rating. Alternate enclosure materials and finishes are available including 11 gauge hot-dipped galvanized types and 0.125” marine grade aluminum types (bare, painted or anodized).
• The C.P. Sentinel Air Series allows full access to the internal components of the rectifier via three hinged and removable doors on the standard enclosure (front and both sides). The rectifier components are assembled onto a single removable frame type assembly.

C.P. Sentinel Oil Series:

• The standard C.P. Sentinel Oil Series enclosure is constructed from 12 gauge mill-galvanized steel with a white fusion bond polyester powder coating and conforms to a Type 4 rating. Recommended alternate enclosure materials and finishes are available including 11 gauge hot-dipped galvanized types. Optional instrument end-housing enclosures are also available.
• The C.P. Sentinel Oil Series allows access to the internal components of the rectifier via a single top hinged lid on the standard enclosure. The rectifier components are assembled onto a single removable frame type assembly and the rectifier bridge specific components are assembled onto a separate frame that can be removed independent of the main frame if required. All major heat generating components are submersed below the oil level in the enclosure. An optional instrument end-housing enclosure to house the rectifier controller, input circuit breaker, meters and connection terminals is recommended.

C.P. Sentinel Air or Oil Series:

• As the required AC input voltage and DC output voltage and current ratings can vary widely based on the geographic region and application, the C.P. Sentinel Series has the flexibility to meet the majority of requirements.
• The C.P. Sentinel (“ON” or “IR-Drop Free” Potential Control) Series rectifier utilizes our revolutionary Sentry controller (or Tri-Sentry controller, for three-phase applications) to automatically adjust the rectifier DC output to maintain the structure to reference electrode potential selected by the operator. In addition to the potential control mode, alternate modes of automatic operation included with this series are constant current control and constant voltage control as well. The Sentry controller provides near infinite output adjustment steps, exceptional output stability (within +/- 5 millivolts of the selected potential set point and +/- 2% of the selected current or voltage set point) and reference electrode input impedance of > 20 megaaohms.
• For C.P. Sentinel Series rectifiers configured for “IR-Drop Free” potential control, the Sentry controller minimizes the IR drop error in the potential measurement by taking the measurement when there is no rectifier current flow in the anode to structure circuit. ***Note: The “IR-Drop Free” potential control mode is only available on single-phase type rectifiers without any DC output filtering.
• The Sentry controller also includes a ‘Loss-of-Reference” shut down feature, which ensures that, should the reference electrode connection or the reference electrode itself fail, the DC output of the rectifier will not increase to maximum to try to restore the selected structure to reference electrode potential level. Instead, the Sentry controller will turn off the DC output until the reference electrode input issue is corrected. This ‘Loss-of-Reference” shut down feature will prevent the possibility of a coating failure that can be caused when excessive Cathodic protection levels are applied to well coated structures.
• The interruption of “automatic” control type rectifiers has historically been a nightmare due to the “over shoot” or “spiking” of the rectifier DC output level as the rectifier controller strives to maintain the pre-set DC output level immediately following the interrupt “OFF” cycle. The “over shoot” issue would affect the ability to accurately measure structure-to-soil potentials during CP performance evaluation testing. In certain instances, it even resulted in damage to the rectifier itself. However, thanks to our revolutionary Sentry series of controllers (Sentry, VI-Sentry and Tri-Sentry); this is no longer an issue. Our Sentry series of controllers incorporate innovative “anti-spiking” circuitry that ensures the rectifier returns to the established set point immediately (and cleanly) after the interrupt “OFF” cycle thus eliminating the “over shoot” issue. ***Note: For rectifiers configured for “IR-Drop Free” potential control, external interruption of the rectifier is not recommended because this could interfere with the rectifier control.
• The C.P. Sentinel (“ON” or “IR-Drop Free” Potential Control) Series includes three continuous reading meters for monitoring of the DC output voltage, DC output current and the structure to reference electrode potential ***Note: For rectifiers configured for “IR-Drop Free” potential control, and for the benefit of the operator, the potential meter will display the “IR-Drop Free” potential, not the “ON” potential.
• High energy surge/lightning protection devices come as a standard feature on the AC input and the DC output of all C.P. Sentinel Series rectifiers. These provide excellent protection for all but the most extreme surge and lightning prone areas. Should the application require even more advanced surge protection, other optional devices can be made available as well.
• For those applications where optional features will be beneficial, the C.P. Sentinel Series has a wide variety of useful optional features that can be incorporated. Some common optional features that, if ordered with the rectifier, can save our clients valuable field time include operational status alarms and remote monitoring equipment.